diff --git a/openbsc/tests/gbproxy/gbproxy_test.c b/openbsc/tests/gbproxy/gbproxy_test.c
index 0ba827f..96a68b0 100644
--- a/openbsc/tests/gbproxy/gbproxy_test.c
+++ b/openbsc/tests/gbproxy/gbproxy_test.c
@@ -1293,6 +1293,7 @@
 	}
 
 	msg = gprs_ns_msgb_alloc();
+	OSMO_ASSERT(msg);
 	memmove(msg->data, data, data_len);
 	msg->l2h = msg->data;
 	msgb_put(msg, data_len);